1. Technical Field of the Invention
The present invention relates generally to electrical generation and energy conversion devices, and more particularly to a fluid-powered energy conversion device that converts the energy of wind or flowing water to mechanical or electrical energy.
2. Description of Related Art
The use of wind or flowing water to provide power for various uses dates back many centuries. In modern times, wind and water have been used to generate electricity. Hydro-electric generating plants have been used to generate large quantities of electrical energy for widespread distribution. However, this requires major permanent environmental changes to the areas where dams are built and reservoirs rise. Wind-powered devices, in general, have been used to perform mechanical work, or to generate electricity, only on a limited scale. With the ever increasing demand for additional or alternative energy sources, all possible sources are being given more scrutiny. This is particularly true for sources that are non-polluting and inexhaustible. Free-flowing hydro-electric and wind-powered systems provide such sources, and the capturing of increased energy from wind and water has received much consideration.
Commercial hydro-electric and wind-powered electrical generation devices that are currently in use, however, have several disadvantages. Wind-powered devices, in particular, are expensive, inefficient, dangerous, noisy, and unpleasant to be around. To capture a large volume of wind, existing wind-powered devices are very large. As a result, they cannot be distributed throughout population centers, but must be installed some distance away. Then, like dams with hydro-electric generators, the electrical energy they generate must be transmitted, at considerable cost and with considerable lost energy, to the population centers where the energy is needed.
It would be desirable to distribute smaller water-powered and wind-powered units throughout the population centers. For example, it would be desirable to have a wind-powered unit for each building structure, thus distributing the generating capacity over the entire area, and making the energy supply less vulnerable to local events such as storms or earthquakes. Such distributed generation would also solve the most common and valid objection to wind power, that is, that the wind does not always blow. In a large geographical area, however, wind is almost always blowing somewhere. Therefore, with wind-powered generators distributed throughout the area, power could be generated in the areas where the wind is blowing, and then transmitted to the rest of the power grid. However, with existing technology, smaller units suitable for distributing throughout a population area are not efficient enough to provide a sufficient amount of energy to power a structure such as a house or office building. In addition, such units are visually obtrusive and noisy, making them unsuitable for use in residential or other highly populated settings.
Existing wind-powered electrical generation devices commonly utilize a propeller mounted on the horizontal shaft of a generator which, in turn, is mounted at the top of a tower. This is an inefficient design because energy is extracted from the wind by reducing the wind velocity as it passes through the propeller. This creates a pocket of slow-moving air centered behind the propeller, which the ambient wind blows around. Therefore, only the outer portion of the propeller blades use the wind efficiently.
To counter this effect, modern windmill designs utilize extremely long propeller blades. The use of such massive blades, however, has its own disadvantages. First, the propellers are known to kill or injure thousands of large birds each year. Second, the massive blades can be dangerous if the device fails structurally and the propeller breaks loose. In this case, the propeller can fly a considerable distance and cause serious damage or injury to anything or anyone in its path. Third, the propeller design contains an inherent gravitational imbalance. The rising blades on one side of the propeller""s hub are opposing gravity, while the descending blades on the other side of the hub are falling with gravity. This imbalance creates a great deal of vibration and stress on the device. At great expense, consequently, the device must be structurally enhanced to withstand the vibration and stress, and thus avoid frequent maintenance and/or replacement.
It would therefore be advantageous to have a fluid-powered energy conversion device that overcomes the shortcomings of existing devices. Such a device could utilize wind energy or the energy of flowing water to provide mechanical energy or electrical energy. The present invention provides such a device.
In one aspect, the present invention is a fluid-powered energy conversion device for converting wind energy into mechanical or electrical energy. The device includes a rigid cylindrical frame having an upstream annular chamber, an intervening turbine, and, a downstream annular chamber, each of the chambers having sides that are open to allow entry of the ambient wind. A first plurality of baffles is longitudinally mounted in the upstream chamber, and operate to create in the upstream chamber, an upstream drive vortex rotating in a first direction when the wind enters the upstream chamber through the upstream chamber""s open sides. A second plurality of baffles are longitudinally mounted in the downstream chamber, and, in devices designed for low-wind conditions, operate to create in the downstream chamber, a downstream extraction vortex rotating in a direction opposite to the first direction when the wind enters the downstream chamber through the downstream chamber""s open sides. In devices designed for high-wind conditions, the baffles in the downstream chamber operate to create an extraction vortex that rotates in the same direction as the drive vortex.
The floor of the upstream annular chamber slopes in a downstream direction as it approaches a central longitudinal axis of the device, thereby causing the drive vortex to flow downstream and pass through a central aperture located between the upstream annular chamber and the downstream annular chamber. The turbine is centrally mounted on a longitudinal drive shaft in the central aperture. The turbine is rotated by the drive vortex as the drive vortex passes through the turbine and combines with the extraction vortex, increasing its downstream velocity.
For low-wind conditions, the first plurality of baffles may be curved to form a toroidal pattern in the first direction, and the second plurality of baffles may be curved to form a toroidal pattern in the opposite direction. The baffles guide the ambient wind into two high velocity vortices (an upstream drive vortex and a downstream extraction vortex) which rotate in opposite directions. The device may also include an annular central divider between the upstream chamber and the downstream chamber that has a downstream surface that slopes away from the turbine as it approaches the central axis of the device. The surface of the central divider thereby causes the extraction vortex to flow downstream, creating an area of reduced air pressure on the downstream side of the turbine. This increases the flow of air from the upstream chamber through the turbine. High RPM and high torque are produced by the turbine due to three primary factors: (1) each blade of the turbine is shaped like a scoop which captures the rotational momentum of the drive vortex; (2) each blade of the turbine has a cross-sectional shape of an airfoil that generates lift in the direction of rotation of the turbine; and (3) the reversal of the direction of the vortex rotation adds additional force to the turbine in the direction of rotation.
A large flywheel may also be attached to the rotating turbine drive shaft. The flywheel may serve both as an internal energy storage device due to its angular momentum, and as a dynamo for a generator also mounted on the drive shaft.
In another aspect, the present invention is a water-powered energy conversion device for converting energy in a moving stream of water into mechanical or electrical energy. The device includes a rigid cylindrical frame having an upstream annular chamber and a downstream annular chamber, each of the chambers having sides that are open to allow entry of the stream of water. A first plurality of baffles are longitudinally mounted in the upstream chamber, and operate to create in the upstream chamber an upstream drive vortex rotating in a first direction when the stream of water enters the upstream chamber through the upstream chamber""s open sides. A second plurality of baffles are longitudinally mounted in the downstream chamber, and operate to create in the downstream chamber a downstream extraction vortex also rotating in the first direction when the stream of water enters the downstream chamber through the downstream chamber""s open sides. A floor of the upstream annular chamber slopes in a downstream direction as it approaches a central longitudinal axis of the device, thereby causing the drive vortex to pass through a central aperture located between the upstream annular chamber and the downstream annular chamber. A longitudinal shaft and a turbine are centrally mounted in the central aperture. The turbine is rotated by the drive vortex as the drive vortex passes through the turbine.
In yet another aspect, the present invention is a fluid-filled flywheel mounted on a drive shaft for reducing start-up inertia of the flywheel and maintaining angular momentum of the drive shaft as it rotates in a direction of rotation. The fluid-filled flywheel includes a hollow disk-shaped shell filled with fluid, and a plurality of radial bulkheads that separate the interior of the shell into separate sections. Each of the radial bulkheads includes at least one gate pivotally mounted thereon to open in a direction opposite to the direction of rotation. Each gate covers an aperture in the bulkhead when the gate is pivoted to a closed position, and each gate opens the aperture when the gate is pivoted to an open position. When the flywheel accelerates in the direction of rotation, the gates are opened by the fluid thus allowing the fluid to flow through the apertures in the bulkheads and reduce the start-up inertia of the flywheel. When the flywheel decelerates, the gates are closed by the fluid thus preventing the fluid from flowing through the apertures, and causing the flywheel to maintain angular momentum like a solid flywheel. The fluid-filled flywheel is particularly efficient when utilized with a wind-powered energy conversion device for which the input energy level varies.